Automated self-propelling endoscope

ABSTRACT

An improved mechanism for an automated self-propelling endoscope. The system augments the conventional “proximal-push” mechanism commonly used in colonoscopy with an innovative “distal-pull” mechanism. The distal-pull mechanism includes external application of a force at the proximal end of the endoscope that is translated into force that is exerted upon and moves the distal (leading) end of the scope further into the colon.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional PatentApplication Ser. Nos. 60/286,366, entitled “Mechanism For AutomatedSelf-Propelling Endoscope,” filed Apr. 26, 2001, and 60/290,658,entitled “Improved Mechanism For Automated Self-Propelling Endoscope,”filed May 15, 2001. The disclosures of these provisional patentapplications are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention relates to an improved mechanism for anautomated self-propelling endoscope.

[0004] 2. Discussion of the Related Art

[0005] The flexible fiberoptic colonoscope has provided directvisualization of the inner surface of the entire colon, and has greatlyinfluenced the diagnosis and treatment of colonic diseases over the pastthree decades. It is pervasively used throughout the U.S. and much ofthe industrialized world. It provides information that is complementaryto common radiologic, CT scan, MRI, and other sophisticated imagingscanning techniques in the diagnosis of colonic disease, and in manycircumstances it is considered to provide the most reliable, efficientand effective available tool. Via instruments inserted through channelsin the scope, a wide array of diagnostic and therapeutic instruments canbe used. However, a major impediment to colonoscopy is the long timethat often is required to examine the full length of the colon. Theintroduction of the scope is in a direction opposite to that effected bynormal peristaltic waves. Further, the tubular colon is tortuous andhighly flexible, and its walls often fail to direct and guide the scopeas it is moved into the colon. As the scope is manually propelled, itenters loops of colon that become “cul-de-sacs” which trap the leadingend of the scope, and prevent the desired retrograde movement of thescope through the lumen. Advancing the scope is reminiscent of attemptsto “push a chain or a flexible rope”. With only manual insertionefforts, progression of the distal end of the scope into the colon issuccessful for the first few short distances; but as the length ofpenetration increases and tortuous configurations of bowel need to benegotiated, the difficulties increase greatly, even with visualdirectional guidance of the tip of the scope. The endoscopist uses avariety of maneuvers to nudge the scope further, including repeatedlyrepositioning the patient (and the colon); utilizing gravity effects tomove the heavier leading end of the scope “downhill”; manipulating thescope against the bowel wall to round corners; applying pressure on theexternal abdomen; altering the rigidity of segments of the scope to moreeffectively translate push-effects distally; changing lumen size andconfiguration with air insufflation; etc. However much endoscopists dosucceed in traversing the entire colon, there is clearly need formechanisms to facilitate the process and to hasten its accomplishment.Many examinations require much time, and many are terminated before theexamination is complete. Thus, a mechanized process that would allowrapid retrograde propelling of the scope to the cecum would be of greatvalue. Colonoscopic examinations are costly, and part of this is due tothe amount of professional time required for the complete examination.In summary, were an automated mechanism available to facilitate rapidtraversal of the colon, it would increase both the effectiveness andefficiency of the wide range of diagnostic and therapeutic uses of theprocedure, and contribute to reducing the financial cost of theprocedure.

[0006] The essence of the problem is to develop a mechanized propellingsystem that is self-contained in the instrument that does not dependupon the external guidance effect of the surrounding highly flexibletubular bowel. Force to insert the colonoscope through the anus into thepatient is simple and straightforward. What is needed is some array oftechnology that would simulate the actions of a “virtual hand” that waslocated in the lumen of the colon just ahead of the tip of theendoscope, and could grasp and pull the tip in the direction of thelumen toward the proximal colon. This is akin to a “Maxwell's demon'shand” that could and would “knowingly” act as needed.

[0007] An analogous problem exists for the small bowel endoscope(enteroscope). The small bowel is about 30 feet long and telescopesitself on introduced instruments. It may take several hours for anenteroscope to traverse major portions of the small bowel. As a result,this is a rarely used procedure.

[0008] Some characteristics of a conventional fiberoptic endoscope(colonoscope) are as follows: the scope is flexible in all directionsalong its central or longitudinal axis; it has a length of about 164 cmand a diameter of about 14.2 mm; the scope includes a fiberoptic viewingchannel and fiberoptic light pipes, and a depth of focus of about 5-100mm; controllable tip deflection of the scope is 180°/180° up/down and160°/160° right/left; and one or more air and water delivery channelsprovided in scope. In addition, a conventional scope typically includesone or more open channels for insertion of instruments for suction,biopsy, surgical incisions, injections, sonography, laser therapy, etc.

[0009] For reasons of safety, comfort to patients, and reduction of timeand costs of colonoscopic (and enteroscopic) procedures, a system whichwould allow automated retrograde introduction of endoscopes thatfollowed the course of the bowel lumen would be highly beneficial. Whenfully introduced in a timely fashion, existing fiberoptic colonoscopesare remarkably effective instruments for a variety of diagnostic andtherapeutic interventions. Over the past two decades, commercialdevelopments have produced small incremental improvements in theendoscopes and the instruments that are. fed through their channels. Theone major innovation over recent years has been the introduction ofscopes by the Olympus Corporation that allows for selective increases ofrigidity of its segments; this has been demonstrated (Brooker, J. C. etal.: Gut; June, 2000: 46:801-805) to be very helpful to the“proximal-push” mechanism which has been and presently remains the mainmode for state-of-the-art propulsion of endoscopes. Nonetheless, manyinvestigators have recognized continuing need for and have attempted toaugment the proximal-push forces with other means to facilitatedelivering the endoscope to the entire target area.

[0010] The related art reveals a variety of approaches that have beentaken to improve the safety, efficacy, comfort, and efficiency ofcolonoscopy. Examples of some different approaches to enhance the designof an endoscope can be seen in U.S. Pat. Nos. 4,054,128, 4,389,208,4,991,957, 5,353,807, 5,482,029, 5,645,520, 5,662,587, 5,759,151,5,819,736, 5,906,591, 5,916,146, 5,984,860, 5,996,346, 6,162,171,6,293,907, 6,309,346, 6,315,713 and 6,332,865. The disclosures of thesepatents are incorporated herein by reference in their entireties. Theefforts to deliver the working end of endoscopes to the sites requiredfor complete examination or treatment of the colon and small bowel haveincluded several different modalities for physically transporting theendoscope into the patient. Yet, the clinical state-of-the-art forcolonoscopy has rested on the decades old “proximal-push technology” asits mainstay, with the recent major improvement offered by introductionof scopes by the Olympus Corporation that allow for selective increasesof rigidity of its segments. Otherwise, technical improvements ofcolonoscopes themselves have been small and incremental; nonetheless,the net result of the numerous small improvements over the years is thecurrent availability of colonoscopes that are technical marvels.Illumination and visual fields; flexibility of the body; universalflexible directional control of the distal end of the scope; air andwater jet delivery channels; one or more small to large channels forinsertion of instruments to provide suction, biopsy, injections,incisions, sonography, laser therapy, etc., etc. attest to the greatversatility and effectiveness of this modality in management ofgastrointestinal disease. Indeed, the proliferation of manysophisticated instruments which are introduced via the scope's channelshas so greatly increased the usefulness of colonoscopy that the lack ofmore major improvements in its own intrinsic technology has beencomfortably tolerated.

[0011] What are the important improvements in current state-of-the-artcolonoscopy that cry out for attention and solution? Mostly they revolveabout the ease, comfort, safety and rapidity of introduction andtraversing of the entire colon for the intended diagnostic and/ortherapeutic purposes. By synthesizing the information in the manypatents listed above, the following points can be observed:

[0012] 1. Major efforts have been expended and are under way to deviseinnovative methods for transporting the endoscope to where it needs tobe with appropriate control, timeliness, safety, ease and comfort; thisconfirms the importance of these continuing needs.

[0013] 2. The proximal-push mechanism is central and necessary forpropelling a colonoscope, but it is not fully sufficient. Manyinvestigators have deliberately attempted to augment the proximal-pushwith other forces to propel the colonoscope to meet the described needs.

[0014] 3. it is becoming progressively more difficult to clearlyidentify the boundaries between technical support of medical/surgicalclinical gastroenterology and the robotics supporting minimally invasivesurgery (MIS).

[0015] 4. In the attempts to innovate more effective endoscopicinstruments, some investigators have developed instruments that come tolook less and less like current endoscopes. Many have substituted newcomplicated technologies that are not superior to current colonoscopesto supplant existing scopes rather than creating new systems that canutilize the very mature, superb existing scopes. Many proposals rely onmoving parts gaining traction against the bowel wall, or pushing on thewall, or that use pneumatic suction to adhere to the wall, all of whichmay alter or injure the mucosa. Others significantly increase the bulkof instruments that are inserted into the colon.

[0016] From these disparate considerations, a new vision crystallized:An improved propelling mechanism for the colonoscope should notsacrifice any meaningful characteristics of today's state-of-the-artcolonoscope. This dictates that an innovative propelling mechanism mustbe engrafted upon today's existing scopes; an innovative propellingmechanism should be implemented which requires no or relatively fewstructural changes of existing colonoscopes, where any changes are sominimal as not to disturb any of their present attributes.

SUMMARY OF THE INVENTION

[0017] Accordingly, it is an object of the present invention to providean improved mechanism for an automated self-propelling endoscope(“scope”) that is highly effective in propelling the scope within thebowels.

[0018] Another object of the present invention is to provide a highlyeffective self-propelling endoscope with minimal alteration to the scopedesign.

[0019] A further object of the present invention is to provide apropelling mechanism for the scope that enhances the classical“proximal-push” mechanism conventionally utilized in the colonoscopeart.

[0020] The aforesaid objects may be achieved individually and/or incombination, and it is not intended that the present invention beconstrued as requiring two or more of the objects to be combined unlessexpressly required by the claims attached hereto.

[0021] According to the present invention, a self-propelling endoscopesystem is established that is capable of converting a colonoscope intoan automated self-propelling colonoscope. In particular, the system ofthe present invention is capable of converting a standard, unmodifiedcommercial colonoscope into an automated self-propelling colonoscopewith no (or minimal) alteration to the colonoscope itself.

[0022] The system augments the classical “proximal-push” mechanism witha “distal-pull” mechanism. The proximal-push mechanism consists simplyof serial insertions of lengths of the scope through the anus into thepatient. The distal-pull mechanism ultimately consists of externallyapplying force at the proximal end of the scope that is translated intoforce that is exerted upon and moves the distal (leading) end of thescope further into the colon. This force translation includes: 1)controlled anchoring of the loop of the scope between sites at theproximal operating end, and immediately external to the anus; 2) aninserted flexible wire obturator having an external wall releasableconnector (e.g., a circumferential inflatable balloon) located justproximal to the scope's flexible leading segment to temporarily bond theleading end of the obturator with the leading end of the body of thescope; and 3) stationary racks with couplings which grasp and eitherhold stationary, or electromechanically move the scope body through theanus into the colon, and in controlled sequence apply the moving forceto the proximal end of the obturator. Various combinations and sequencesof these actions result in specific patterns of scope locomotion that,when integrated and cyclically repeated, facilitate the automatedself-propelling mechanism for the endoscope. In other embodiments, minormodifications of the colonoscope provide other mechanisms accomplishingthe propelling mechanism. All propelling movements, as described indetail below, may also be performed manually by assistants to theendoscopist.

[0023] The above and still further objects, features and advantages ofthe present invention will become apparent upon consideration of thefollowing definitions, descriptions and descriptive figures of specificembodiments thereof wherein like reference numerals in the variousfigures are utilized to designate like components. While thesedescriptions go into specific details of the invention, it should beunderstood that variations may and do exist and would be apparent tothose skilled in the art based on the descriptions herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1A is an elevated side view in partial section of aself-propelling endoscope system according to the present invention.

[0025]FIG. 1B is a cross-sectional view taken along lines 1B-1B of theendoscope of FIG. 1A.

[0026]FIGS. 2A-2C are elevated side views in partial section of thesystem of FIG. 1A showing the “distal-pull” effect exerted from theproximal end of the endoscope.

[0027]FIG. 3 is a side view in partial section of another embodiment ofa self-propelling endoscope system according to the present invention.

[0028]FIG. 4 is a side view in partial section of the system of FIG. 3showing a completed cycle of strong “proximal-push” and “distal-pull”effects.

[0029]FIGS. 5A and 5B are side views in partial section of the system ofFIG. 3 showing operation of the clamps at the Rack Two location of thesystem.

[0030]FIG. 6 is a side view in partial section of the system of FIG. 3showing opposing forces acting upon the EXT-obturator of the systemduring a “proximal-push” and “distal-pull” cycle.

[0031]FIG. 7 is a side view in partial section of the system of FIG. 3showing the configuration of the endoscope and obturators after eightcycles of movement by the system.

[0032]FIGS. 8A-8F are views in partial section of alternativeembodiments of a self-propelling endoscope system according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] In an exemplary embodiment of a self-propelling endoscope systemof the present invention includes modification of existing flexibleobturators, and use of external automated controlling mechanisms, butrequires no modification of the endoscope itself. Other embodimentsinvolve slight modification to the endoscope as described below.

[0034]FIGS. 1A and 1B illustrate schematic sagittal (i.e., longitudinalcross-section) and cross-sectional views of the endoscope. The sagittalsection depicts a flexible colonoscope laid out in a linear fashion. Itsessential components are labeled and shown in FIG. 1A. FIG. 1B is aschematic cross-sectional view. Letters “A” through “J” are labels toidentify the following components:

[0035] A). Outer wall of colonoscope.

[0036] B). Wall of “obturator channel” forming the lumen (diameterpreferably in the range of about 3.8-5 mm) through which wire obturatorsare passed. The obturator channel wall is integrally attached to theouter wall of the colonoscope such that movement of the obturatorchannel wall forces corresponding movement of the scope. To allowclarity of illustration, the size of this channel is greatly exaggeratedrelative to the cross-section of the remaining parts of the endoscope.During the automated propelling phase, this channel contains theinserted obturators whose manipulations effect the forward movement ofthe endoscope. However, after the scope has been fully introduced, theseobturators are withdrawn, and the full channel is available for suctionor for insertion of any of the numerous diagnostic and therapeutic toolsavailable.

[0037] C). Wall of outer coiled wire obturator or EXT-obturator,illustrated as a dotted line. The EXT-obturator is highly flexible alongits linear axis, it is non-distensible, and its total length isnegligibly expandable or compressible. It is the vehicle mediating thepropelling system described in detail below. Its distal end protrudesbeyond the distal end of the scope into the colon, and can serve as asuction channel throughout the procedure.

[0038] D). Wall of inner coiled wire obturator or INT-obturator,illustrated as a solid line. It also is highly flexible along its linearaxis, is non-distensible, and its length neither expandable norcompressible. Of the two obturators used in the propelling system, theINT-obturator has the smaller diameter, and is inserted through thelumen of the EXT-obturator. As seen in the cross-sectional view of FIG.1B, the INT-obturator has a lumen that can be used for additionaloptional suction during the propelling phase. It has no role in thepropelling mechanism, and, optionally, may not be included duringpropelling of the scope as described below. The lumen of theINT-obturator is not depicted in FIG. 1A; rather, the INT-obturator isrepresented as one single wide line to facilitate visualizing therelationships between the two obturators.

[0039] E). Fiberoptic channel and other functional components. Together,all of these components are rendered as a single dashed line in thefigures. The fiberoptic channel is located in the space within thecolonoscope's outer wall, and is external to the obturator channel. Theseveral other functional elements that are similarly located in thisspace which are not separately depicted graphically are represented bythis same dashed line; included are channels for fiberoptic light-pipes;guide-wires for universal directional flexing of the leading tip of thescope; air inflation; and water inflation. Together, these “E” elementsmake up the bulk of the cross-sectional content of the endoscope.Consider all of these elements as a bundle that constitutes the majoroperating end of the scope held by the endoscopist. The “E” bundle isseparated from the obturator channel and its contents near the proximalend of the scope. The curved pathway of the dashed line is meant toconvey the physical separateness and mobility of the operating end ofthe scope, so that the endoscopist can integrate and control the usualtasks with those associated with the automated propelling operation. Tofacilitate description of the system, the size of the obturator channeland its contents is grossly exaggerated in the figures, and the proximalend of the obturator channel is depicted in straight continuity with theremaining portion throughout the length of the scope. However, theobturator channel may include other configurations (e.g., this channeltypically includes a small side channel coming off of the larger body ofthe endoscope).

[0040] F). Flange secured to the proximal end of the scope and theproximal end of the obturator channel. This flange, when grasped andheld in a fixed position by a coupling mechanism (dotted line) of RackOne (I) stabilizes the spatial position of the proximal end of theautomated propelling mechanism.

[0041] G). Flange secured to the proximal end of the EXT-obturator. Thisflange, when grasped and held in a fixed position by another couplingmechanism (dotted line) of Rack One, controls the movement of theEXT-obturator. A motor within Rack One exerts intermittent controlledtiming of controlled variable force on the flange to move theEXT-obturator forward (i.e., from left to right in FIGS. 1A and 1B) orbackward (i.e., from right to left in FIGS. 1A and 1B).

[0042] Since the INT-obturator serves as an optional suction conduit,the operator may choose to manually control its placement and movement.If desired, an alternative is to couple the EXT-obturator and theINT-obturator to maintain a constant spatial relationship therebetween.

[0043] I). Rack One. Rack One sits upon and is strongly fastened to aplatform or table (not shown) located adjacent to the proximal end ofthe endoscope. This stabilizes the proximal region of the scope distalto where the endoscopist holds its major operating end. Rack One has twopotential coupling mechanisms attached to flanges F and G. One couplingmechanism couples to flange F and holds the obturator channelimmobilized at a fixed point in space. The other coupling mechanismcouples to flange G and holds the EXT-obturator and, as programmed,either holds it motionless, or as force is applied, moves the obturatorforward. Rack One further includes a controller and/or other suitablecomponents (e.g., motors or other electromechanical components) tocontrol movement of the coupling mechanisms thereby effecting automatedmovement of the EXT-obturator and the obturator channel.

[0044] J). A mechanism to reversibly bond the distal end of theEXT-obturator with the distal end of the scope's channel wall. In anexemplary embodiment, this is accomplished by inflation of acircumferential cylindrical balloon on the outer wall of theEXT-obturator. (Alternatively, a series of closely adjacent smallerballoons may be used to avoid this segment of the scope losing itsflexibility as the balloons are inflated).

[0045] A “distal-pull” effect exerted from the proximal end of anendoscope in a simplified linear configuration model is now described inrelation to FIGS. 2A-2C. FIGS. 2A-2C illustrate, in a simplified modeland a linear configuration, the steps by which manipulation of theEXT-obturator can exert a distal-pull effect on a flexible endoscope.FIG. 2A shows the endoscope lying on a flat surface in a linearconfiguration. In FIG. 2A the two coupling mechanisms of Rack One areshown as grasping and holding stationary the proximal end flanges F andG of the obturator channel wall and the EXT-obturator, respectively.Releasable bonding of the distal ends of the EXT-obturator and theobturator channel is provided with the inflated balloon J. As previouslynoted, this releasable bonding may be provided with any other suitablemechanism.

[0046] In FIG. 2B, the Rack One instructions are to release the flangeto the proximal end of the scope and to grasp and exert forward (i.e.,left to right) force on the EXT-obturator flange, shown by the arrow inthe Rack One box, to move it one unit distance. Because the distal endof the EXT-obturator is bonded to the channel wall, the forward thruston the EXT-obturator pushes the distal end of the obturator channelforward along with the entire endoscope which is integrally attached toit. Thus, the effect is the same as manually grasping the distal end ofthe scope and pulling it forward (i.e., to the right as illustrated inFIGS. 2A-2C). In this linear configuration, it is easy to see that forceexerted at the proximal end of the scope (i.e., on the flange of theEXT-obturator) simulates the effects of an external pulling forceexerted on the distal end of the scope. To use this effect in areal-life endoscopy context, a major challenge involves devising asystem in which such a “distal pull” can be effected when the scope isnot in a linear configuration, but rather follows multiple curvesoutside the body and as it moves through the bowel. As the scope movesforward (i.e., to the right in FIGS. 2A-2C), the INT-obturator, havingbeen held motionless, no longer protrudes beyond the distal end of thescope.

[0047] In FIG. 2C, the Rack One instructions are to hold the flanges ofthe proximal ends of the scope and EXT-obturator motionless, andmanually the INT-obturator is moved one unit distance forward. Thiscompletes one full cycle, re-establishes the spatial relationshipsbetween the endoscope and the two obturators as illustrated in FIG. 2A,and the entire scope has been moved forward one unit distance (i.e.,compare the positioning of the endoscope in FIGS. 2A and 2C).

[0048] Another embodiment of the present invention is depicted in FIGS.3-7. This system is similar to the system of FIGS. 1-2 and includes aRack Two K, which is similar in design and operability to Rack One. EachRack One and Rack Two includes coupling mechanisms as described below toeffect movement of the EXT-obturator C and obturator channel B asdescribed below. This system also illustrates a “distal-pull” effectexerted from the proximal end of an endoscope in a real-lifeconfiguration involving tortuous path rather than linear movementconfigurations. To explain the “distal-pull” effect in this system, itis necessary to (A) describe the operational configuration of theendoscope in actual practice; (B) detail the functions of Rack One andRack Two of the system as to their respective roles in contributing toforward (i.e., left to right as illustrated in FIGS. 3-7) motion of theendoscope; and (C) describe integration of the various components in thesystem to accomplish the automated propelling motion.

[0049] A. Operational Configuration of the Endoscope in Actual Practice

[0050] The operational configuration of the endoscope in actual practiceis represented in FIG. 3. The proximal controls of the endoscope fordirecting the distal tip, water and air insufflation, fiberoptic lightpipes, and the optical channel for visualizing the gut are bundledtogether (depicted as dashed line E) and held by the endoscopist. Theproximal end of the obturator channel F is held in a fixed position bythe Rack One coupling mechanism. This defines the beginning of a longloop formed initially between the operating proximal end of the scopeand the distal end of the scope that is manually inserted through theanus into the distal colon. The stability of the proximal end of thescope is enhanced by a firm coupling to a rigid ring L through which thescope passes. The scope is also firmly coupled and firmly supported by asecond ring N through which the scope passes. Operationally, the end ofthe loop of the scope is at the anchored point M. The rings L and N arerespectively coupled (see dashed lines in FIG. 3) to Rack One I and RackTwo K.

[0051] Rack Two provides stationary stable support for the colonoscopebeyond the loop by two sets of clamps, disposed at point M in FIG. 3.The two sets of clamps work alternately as described below. At all timesthrough a cycle, one or the other of the clamp sets is holding andcontrolling the location of the body of the scope in this region. At thebeginning and end of each cycle, one or the other set of clamps fixesthe endoscope at point M. Together, the coupling mechanisms coupled toflange F and point M provide two stationary points in space at which theproximal end of the obturator channel and the immediate post-loopcolonoscope are continuously anchored, allowing for complete control ofthe length of the loop between them, and assuring that there is noincrease in the length of the loop when forces are applied to the scope.The importance of this for the propelling mechanism is described below.

[0052] Consider FIG. 3 as the baseline stage at which the endoscopisthas manually advanced the endoscope under visual guidance as far intothe rectosigmoid area as is practical, and where use of the automatedpropelling activity is then considered. The EXT-obturator is fullyinserted into the scope channel. A fine plastic tube extending along itsentire length allows its distally located balloon J (or other suitablebonding mechanism) to be inflated from an external position. Inflationof the circumferential balloon serves as a circumferential wedge in thespace between the EXT-obturator and the obturator channel, therebybonding the two. When the EXT-obturator is moved, it drags the distalend of the scope with it. Comparison of FIG. 4 with FIG. 3 shows theeffects of one full propelling cycle. Note the limited areas ofbackground gridlines that allow easy comparison of the movements andpositions of the colonoscope and the obturators as cycles of thepropelling mechanism are activated and changes are shown in sequentialfigures.

[0053] B. Detailed Description and Functions of Rack One and Rack Twofor Propelling the Eendoscope Forward

[0054]FIG. 3 depicts Rack One and Rack Two at the beginning of apropelling cycle. Rack One sits upon and is strongly fastened to aplatform or table located adjacent to the proximal end of the endoscope.It has two potential coupling mechanisms, each designated by a dottedline when active. In FIG. 3, the vertical line attached to the couplingof the proximal end of the obturator channel F establishes a fixed andstable location for it; the proximal end of the obturator channel doesnot change its location during the entire operation of the automatedpropelling operation. This stability is enhanced by a similar firmcoupling to rigid ring L through which the scope passes. Beyond the ringL is the loop that consists of the major length of the endoscope. Thecoupling mechanism at point G, including a pair of clamps, holds theEXT-obturator stationary with respect to Rack One I.

[0055] Electrical motors of Rack One provide variable controlled levelsof force to be exerted on the coupling of the obturator. The criticaleffects of forward (i.e., left to right) force exerted on theEXT-obturator are described as follows.

[0056] As illustrated in FIGS. 5A and 5B, Rack Two K sits upon and isstrongly fastened to a platform or table located adjacent to thepatient's anal insertion area. Rack Two controls two sets of alternatingclamps at point M. Specifically, FIG. 5A illustrates the movements ofone set of two clamps located at 12 o'clock and 6 o'clock on thecircumference of the endoscope at point through the course of one timecycle. At the beginning of a first cycle, the two clamps of the firstset grasp the top and bottom surfaces of the colonoscope. Force isexerted on the set of clamps, via Rack Two, to move them from theproximal, or left, to the distal, or right, position (as shown by thearrow in the Rack Two box of FIG. 5A), thereby moving the scope forwardinto the patient by one unit length (also indicated by dotted arrows inFIG. 5A). The clamps are released at the end of the first cycle. Duringthe second cycle, the released clamps are returned to their originalproximal position. In the third cycle, the steps of the first cycle arerepeated.

[0057]FIG. 5B summarizes actions in the second cycle in which two clampsof the second set at point M, located at 3 o'clock and 9 o'clock on thecircumference of the endoscope, perform similarly. That is, at thebeginning of the second cycle, these two clamps grasp the two sides ofthe colonoscope. For purposes of convenience, the obturator channelwall, INT- and EXT-obturators and bundle of wires E are not shown inFIG. 5B. Force is applied, via Rack Two, to move these clamps from theproximal to the distal position (as shown by the arrow in the Rack Twobox of FIG. 5B), thereby moving the scope forward into the patient byone additional unit length. The clamps are released at the end of thesecond cycle. During the third cycle, the released clamps are returnedto their original proximal position. In the fourth cycle, the steps ofthe second cycle are repeated. Thus, the two alternating sets of clampsserve both to move the scope and to be a continuous anchor of theendoscope at point M at the end of each cycle. They provide a smoothforward motion of the scope into the patient. Variable controlled levelsof force to be exerted on the sets of clamps are provided by electricalmotors of Rack Two.

[0058] A similar coupling-clamp mechanism is used to move theEXT-obturator forward by force applied to its proximal end at point G(see FIG. 3), resulting in forward (i.e., left to right) motion of thescope. Because of the smaller diameter of the EXT-obturator, the twosets of clamps are mounted on adjacent serial segments rather than ondifferent parts of the circumference of the same segment.

[0059] C. Integration of the Various Components of the System toAccomplish the Automated Propelling Motion.

[0060] In the system described above, the transit of the endoscope fromthe distal toward the proximal colon is effected through two sets ofactions: one is the “proximal-push” effect and the other is the“distal-pull” effect. The simultaneous combined use of automatedproximal-push and distal-pull mechanisms greatly facilitates rapidtransit of the scope from the distal colon to the cecum.

[0061] Initially, the proximal-push effect is begun by manuallyinserting the scope through the anus into the rectum and pushing it intothe sigmoid area. With only manual insertion efforts, progression of thedistal end of the scope into the colon is successful for the first fewshort distances; but as the length of penetration increases and tortuousconfigurations of bowel need to be negotiated, the difficulties mayincrease meaningfully, even with visual directional guidance of the tipof the scope. The endoscopist uses a variety of maneuvers to nudge thescope further, including repeatedly repositioning the patient (and thecolon); utilizing gravity effects to move the heavier leading end of thescope “downhill”; manipulating the scope against the bowel wall to roundcorners; applying pressure on the external abdomen; altering therigidity of segments of the scope to more effectively translatepush-effects distally; changing lumen size and configuration with airinsulation; etc. However much endoscopists do succeed in traversing theentire colon, there is clearly need for mechanisms to facilitate theprocess and to hasten its accomplishment.

[0062] Consider the isolated proximal-push effect of the two sets ofclamps controlled by Rack Two at point M. The alternation of the twosets of clamps essentially provides a controlled automation of the usualmanual insertion efforts described above. However, even using thesupportive manipulations described above, successful negotiation of theentire colon by this method alone often is problematical.

[0063] Consider one cycle of activity of the propelling system in whichthe proximal-push effect of Rack Two is dominant and strong, and therealso is a strong distal-pull effect of Rack One. Comparison of FIG. 3 asthe initial state prior to the cycle, with FIG. 4 as the end of thecycle allows analysis of the interacting changes that occur. The RackTwo clamps at point M close firmly on the endoscope; left to right forceis applied by the Rack Two coupling mechanism, moving the clamps oneunit length from their proximal to their distal positions; and theterminal portion of the endoscope likewise is pushed one unit distanceinto the patient. At the end of the cycle, the second set (3 o'clock and9 o'clock) of clamps close firmly on the scope at point M. Becausepoints F and M are fixed in space, the one unit length of theendoscope's advance into the patient (seen on the grid) requiresshortening of both the descending and ascending limbs of the loop byone-half unit distance each (easily seen by the rise of the trough ofthe loop by one-half of a grid length in FIG. 4).

[0064] Simultaneously, there is a strong Rack One distal-pull effect.Such an effect is symbolized in FIG. 4 by the arrow in the Rack One boxrepresenting left to right force applied to the clamps at point Gholding the EXT-obturator during the cycle. The simultaneous forceapplied to the EXT-obturator creates a potentiating distal-pull effect;the two forces applied simultaneously accomplish the forward movementmore easily. Importantly, the distal-pull effect additionally moves theleading end of the scope further into the bowel, and straightens outredundant and loose tortuous loops of the scope lying in the colon.

[0065] Next, consider one additional cycle of activity in which both theproximal-push effect of Rack Two and the distal-pull effect of Rack Oneare both strong. Comparison of FIG. 4 as the initial state prior to thissecond cycle with FIG. 6 as the end of the cycle, shows another unitdistance advance of the scope, and additional shortening of both limbsof the scope's loop (FIG. 6). It is important to understand theinteractions between the proximal-push and distal-pull mechanisms.Consider the consequences of strong constant force applied to move theEXT-obturator coupler of Rack One forward (i.e., to the right),symbolized by the left-to-right arrow applied to the coupler in FIG. 6.As the entire EXT-obturator is moved forward by this force, the entiredistal segment of the endoscope to which it is integrally bound alsomoves to the right. Thus, this set of forces manifests the desired“distal-pull” effect on the distal end of the scope. Under theendoscopist's visual guidance and manipulation of the scopes tip'sdirection, the leading end of the scope is “pulled” into the open lumenpathway before it. The “distal-pull” effect of Rack One is simultaneouswith and complementary to the “proximal-push” effect of Rack Two.

[0066] Further, consider the movement and spatial location of theEXT-obturator during this cycle ending as depicted in FIG. 6. During thecycle two opposing sets of forces act upon the sets of clamps at pointG, represented by the two opposing arrows in FIG. 6. The first force,indicated by the left-to-right arrow, represents displacement to theright as left-to-right force is exerted on it to create the“distal-pull” effect. An opposing second set of forces (theright-to-left arrow) is dictated by the requirement that, at the end ofeach cycle, the spatial relationship of the EXT-obturator to theproximal end of the obturator channel must be the same as at thebeginning of the cycle. This opposing set of forces tends to return theRack One coupler toward its initial position. Briefly, the opposingforces can be explained as follows. At the end of cycle two, thecombined Rack Two “proximal-push” and the Rack One “distal-pull” effectshave moved the endoscope one unit distance into the patient. Becausepoints F and M are fixed in space, the one unit length of theendoscope's advance into the patient in this cycle (seen by changes ofposition on the grid. in FIG. 6) requires another shortening of both thedescending and ascending limbs of the loop by one-half unit distanceeach. Since the length of the EXT-obturator (from point G proximally toits distal end) is constant, and its.distal end is bonded to the distalend of the scope so that it cannot move beyond the distal end of theobturator channel, the shortening of the loop (driven by theproximal-push mechanism) forces the EXT-obturator coupling to returntoward its original starting position. Because of the temporalcoordination of the Rack Two proximal-push and the Rack One distal-pulleffects, it is possible to greatly vary the amount of left-to rightforce applied to the EXT-obturator to obtain the desired distal-pulleffect while causing only small amounts of displacement of theEXT-obturator coupler clamps. Thus, the mix of forces providingproximal-push and distal-pull effects can be varied greatly. The timingand magnitude of the two automated applied forces may be controlled bythe endoscopist.

[0067] Generally speaking, the Rack Two effect has greater influence onmoving the proximal segments of the scope, while the Rack One effect hasgreater influence on moving the distal segment of the scope. Returningto an earlier analogy, the Rack Two effect in isolation mimics thedifficulty of trying to push a flexible rope from its proximal end. Thecombined Rack One and Rack Two effect is analogous to moving a rope bysimultaneously moving its proximal and distal ends in a coordinatedfashion. The proximal-push and the distal-pull mechanisms jointlycontribute to the forward propelling motion: additionally, thedistal-pull mechanism further advances the tip of the scope as itstraightens tortuous and redundant curves of the scope in the colon.

[0068] During the cycle, the INT-obturator may be moved in and outmanually and used for suction; or it may be removed and not used.

[0069] In some circumstances, the Rack One effect may be exerted alone.That is, the Rack Two proximal-push effect is not activated and simplyholds the scope motionless at the point M location while forwardpressure is exerted on the EXT-obturator coupling at point G to create adistal-pull effect. Such a maneuver further advances the tip of thescope by tightening loose and tortuous configurations of the scoperelative to the bowel in which it lies between the anus and the distaltip of the scope.

[0070] Occasionally, this mechanism is used in reverse. In manycircumstances, the endoscopist cannot identify the direction of thecolon lumen; its appearance is confounded with cul-de-sacs orconvolutions of loops of bowel segments. To address this problem, it isnecessary to pull the endoscope partially out, and then explore duringre-entry. By combining a static proximal-push mechanism (i.e.,continuous anchoring of the scope at point M) with pulling or backward(i.e., right to left) movement of the proximal end of the EXT-obturator,the distal end of the EXT-obturator may be partially withdrawn, carryingwith it the bonded distal segment of the endoscope. This avoids a majorwithdrawal by externally pulling the entire scope through the anus. Itprovides additional operational versatility to the colonoscopist forreaching the cecum.

[0071] The system illustrated in FIGS. 3-7 for automated propelling ofan endoscope through the colon is based on the synergistic use of thetwo mechanisms described above. The first mechanism consists of repeatedcycles, mediated through Rack Two, providing a “proximal-push” mechanismthat progressively moves the endoscope through the anus into the colon.The duration of each cycle and the length of the segment of theendoscope moved forward in each cycle (hence, the linear rate of thescope's introduction into the patient) can be varied, and are under thecontrol of the endoscopist. Additionally, the amount of Rack Two forceapplied in the cycles to effect the scope's forward movement through theanus is variable and controllable, so that sufficient but not excessivelevels of force can be used.

[0072] The second mechanism, mediated through Rack One, provides forforce applied to the proximal end of the EXT-obturator to be translatedthrough the obturator channel and serve as a simulated “distal-pull”effect on the distal end of the scope. Rack One cycles are temporallycoordinated with Rack Two cycles. In one of the examples describedabove, both proximal-push and distal-pull effects were strong. Inanother example described above, the distal-pull effects were used alonewhen the scope within the colon has loose, redundant tortuosities andcurvatures that need to be straightened. The endoscopist can control therelative strengths of both methods used for propulsion. Given that theproximal-push has a predominant effect on the more proximal portion ofthe scope, and that the distal-pull has a more predominant effect on thedistal portion of the scope, clinical experience will allow theendoscopist to vary the uses of the two mechanisms'characteristics atsequential stages of the procedure as he or she fashions the mosteffective use of these capabilities. The flexibility to do so is builtinto the system.

[0073] In FIGS. 3-7, two cycles of the proximal-push in combination withthe distal-pull effects have been described. Repeating cycles in amanner described above allows the scope to traverse the colon from therectosigmoid area to the cecum. In FIG. 7, a schematic illustration ofthe system is depicted after six additional cycles have occurred and thescope has negotiated curves to advance a total of 8 unit lengths. Pointsare labeled in FIG. 7 to depict the following travel path for the scope:“0” indicates where the end of the scope was at the point of thebeginning of the first cycle; “1, 2, 6 and 8” indicate locations of thedistal end of the scope after completion of corresponding automatedpropelling cycles. Each cycle results in one unit length progression ofthe distal end of the scope, indicated approximately as the distancebetween grid lines depicted. in FIG. 7. Comparison of FIG. 3 (prior tothe first automated cycle) with FIG. 7 (after completion of eightautomated cycles) shows that the scope's forward progression of eightunit lengths through the colon occurs at the expense of the loop whosedescending and ascending limbs each are four unit lengths shorter.

[0074] Of critical importance is the system's behavior as the leadingtip of the endoscope approaches curved loops of colon. As theendoscopist visualizes such curves, the direction of the tip of thescope is manipulated so that its linear axis lines up with the linearaxis of the gut lumen immediately ahead of it. Since the effective siteof the distal-pull effect is very close to the terminal end of thescope, its thrust should support forward movements of the scope into thelumen opening ahead of it; repeated small steps may be needed tonegotiate severe curves. The resistance of the bowel wall to deformationmay be recruited to help guide the scope around such curves. Additionalcycles add to the progression of the endoscope, until it reaches thececal area. Once reached, the endoscopist can disengage the automatedpropelling system, and revert to the customary procedures forexamination of the colon as the colonoscope is manually withdrawn. As itis withdrawn, the obturator channel is available for insertion of any ofthe diagnostic or therapeutic tools needed as determined by theendoscopist's findings.

[0075] It is important to avoid application of excessive forces. Sincemovement of the endoscope is largely effected by means of force exertedthrough Rack One and Rack Two motors, mechanisms may be instituted toprevent excessive force being exerted on the colon. For example,pressure sensors on the leading tip of the endoscope and/or of theobturators can be programmed to alarm the operator, and to interruptcontinuation of the propelling mechanism when specified pressure levelsare exceeded.

[0076] Several alternative technologies to support the “distal-pull”effect are illustrated in FIGS. 8A-8F. In FIG. 8A, the releasablebonding mechanism J includes a retractable flange that is extruded fromthe distal wall of the obturator channel into the lumen against whichthe EXT-obturator abuts. Forward or left-to-right force applied to theproximal EXT-obturator coupling is translated to, and moves the distaltip of the scope forward. Creating the retractable flange entailsengineering changes of the colonoscope.

[0077] In FIG. 8B, a gap in the distal wall of the obturator channelserves as a receptor for a stent-like protrusion from the distal end ofthe EXT-obturator. The stent-like protrusion can be controlled by theendoscopist to engage the gap and thus serves as the releasable bondingmechanism J and a functional alternative to the retractable flange ofFIG. 8A.

[0078] In FIG. 8C, the releasable bonding mechanism J includes a tip onthe EXT-obturator that abuts extruded flanges in the distal obturatorchannel. Alternative force mechanisms can also be used. For example,once the tip of the EXT-obturator is abutted to the retractable flanges,the tip of the EXT-obturator can have force applied via an expandablesection (i.e., the large dashed extension depicted in FIG. 8C)controlled from the outside by the endoscopist. The force exerted couldbe from an electronically controlled solenoid or linear activator; orfrom high-pressure injection of gas or water through a fine tube runningthe length of the obturator.

[0079]FIG. 8D depicts a semilunar or rectangular shaped metal flap whichis installed on the leading edge of the scope and serves as thereleasable bonding mechanism J and a substitute for the retractableflange of FIG. 8A. Its position would line up directly with a dedicatedobturator lumen, so that the transmission of force function of theEXT-obturator would be exerted directly on it. It could be small enoughso that there would be no compromise of other needed endoscopicfunctions.

[0080] Separate channels can also be used for the EXT-obturator andINT-obturator functions. As illustrated in FIG. 8E, one channel would beused for suction (via the INT-obturator) and a second dead-end channelwould be used for the force translation effects from the EXT-obturator.

[0081] For very long scopes (e.g., the enteroscope), three channelscould be used to add a mid-scope distal pull effect such as the scopedepicted in FIG. 8F. Separate channels could be used for theEXT-obturator and INT-obturator functions. As shown, one channel wouldbe used for suction (via the INT-obturator), a second dead-end channelwould be used for the force translation effects from the EXT-obturatoron the distal end of the scope, and a third channel that was dead-endedat mid-distance from the two ends of the scope would be used for anadditional EXT-obturator for force translation effects on the middlesection of the scope. (For the mid-scope effect to succeed, the dead-endof that channel needs to be directly bonded to the external scope wallto mediate the distal-pull effect.)

[0082] The systems of the present invention are not limited toendoscopes for use in the colon; rather, the systems described above arealso relevant to enteroscopes and to endoscopes for examination of othertubular organs and structures. For example, the mechanisms describedabove for the colonoscope can be, with some minor modifications,translated directly into use for automated rapid propelling of anenteroscope through the stomach, duodenum, jejunum and ileum. Itspotential for improving diagnostic and therapeutic approaches to thesmall bowel is clear. Miniaturized versions of the propelling mechanismof the present invention can be useful for advancing small cathetersinto: the gall bladder and hepato-biliary ducts; pancreatic ducts;ureters and kidneys; uterus and Fallopian tubes; and blood vessels ofmany organs. Enlarged versions of the propelling mechanism can be usefulfor non-medical applications such as advancing non-rigid instruments toidentify and remedy disturbances of plumbing and fluid pumping systems,etc.

[0083] Having described preferred embodiments of a new and improvedautomated self-propelling endoscope, it is believed that othermodifications, variations and changes will be suggested to those skilledin the art in view of the teachings set forth herein. It is therefore tobe understood that all such variations, modifications and changes arebelieved to fall within the scope of the present invention as defined bythe appended claims. Although specific terms are employed herein, theyare used in a generic and descriptive sense only and not for purposes oflimitation.

1. A system for self-propelling a colonoscope within an intestinecomprising: a scope housing; an obturator channel disposed within andextending between proximal and distal ends of the scope housing, whereinthe obturator channel is secured to the scope housing such that movementof the obturator channel effects movement of the scope housing; anobturator disposed within the obturator channel and extending beyond theproximal end of the scope housing, wherein the obturator is secured to asection of the obturator channel at a securing location proximate thedistal end of the scope housing; and a pull control device coupled tothe obturator at a coupling location proximate the proximal end of thescope housing, wherein the pull control device is configured to apply aforce upon the obturator at the coupling location to effect applicationof a corresponding pulling force on the obturator channel at thesecuring location and the distal end of the scope housing resulting in acorresponding movement of the distal end of the scope housing into theintestine that increases an intestinal path distance between the distalend of the scope housing and an insertion point of the scope housinginto the intestine.
 2. The system of claim 1, wherein the pull controldevice is further configured to control the force applied to theobturator to effect corresponding movement of the distal end of thescope housing in a direction that decreases the intestinal path distancebetween the distal end of the scope housing and the insertion point. 3.The system of claim 1, further comprising: a bonding mechanism toreleasably secure the obturator to the obturator channel section.
 4. Thesystem of claim 3, wherein the bonding mechanism includes an inflatableballoon surrounding an outer surface of the obturator.
 5. The system ofclaim 1, further comprising: an internal obturator insertable andextendable between proximal and distal ends of the obturator; and afiberoptic channel disposed within and extending between the proximaland distal ends of the scope housing.
 6. The system of claim 1, furthercomprising: a push control device coupled to the scope housing aselected distance from the proximal end of the scope housing, whereinthe push control device is configured to apply a pushing force to thescope housing in a direction corresponding to the force applied to theobturator by the pull control device.
 7. The system of claim 6, whereinthe system prevents any movement of the proximal end of the scopehousing in response to the forces applied by the push and pull controldevices, the scope housing includes a looped section situated betweenthe push and pull control devices, and the looped section of the scopehousing decreases in length as the intestinal path distance between thedistal end of the scope housing and the insertion point is increased. 8.The colonoscope of claim 7, wherein each of the push and pull controldevices includes a supporting ring configured to support an end of thelooped section such that the scope housing is maintained at a desiredposition in relation to the push and pull control devices.
 9. Thecolonoscope of claim 6, wherein the pull control device includes aclamping element movable in relation to the pull control device andconfigured to releasably secure to the obturator, the push controldevice includes a clamping element movable in relation to the pushcontrol device and configured to releasably secure to the scope housing,and each of the push and pull control devices is further configured tocontrol movement and securement of the respective clamping device so asto effect application of a respective one of the pushing and pullingforces.
 10. The colonoscope of claim 9, wherein each clamping element ofthe push and pull control devices includes a first pair of opposingclamps and a second pair of opposing clamps spatially offset from thefirst pair of opposing clamps, and each of the push and pull controldevices is further configured to selectively alternate control ofmovement and securement between the respective first pair of opposingclamps and the respective second pair of opposing clamps to effectapplication of the respective one of the pushing and pulling forces. 11.A system for propelling a hollow probing member through a tunnel,wherein the probing member includes an internal member disposed withinand protruding from a proximal end of the probing member, the internalmember being secured to an internal section of the probing member at asecuring location proximate a distal end of the probing member, thesystem comprising: a pull control device including a coupling membersecurable to the internal member at a coupling location proximate theproximal end of the probing member, wherein the pull control device isconfigured to apply a force to the internal member at the couplinglocation to effect application of a pulling force at the distal end ofthe probing member resulting in a corresponding movement of the distalend of the probing member into the tunnel that increases a tunnel pathdistance between the distal end of the probing member and an insertionpoint of the probing member into the tunnel.
 12. The system of claim 11,wherein the pull control device is further configured to control theforce applied to the internal member to effect corresponding movement ofthe distal end of the probing member in a direction that decreases thetunnel path distance between the distal end of the probing member andthe insertion point.
 13. The system of claim 11, further comprising: apush control device including a coupling member securable to the probingmember, wherein the push control device is configured to apply a pushingforce to the probing member in a direction corresponding to the pullingforce applied to the distal end of the probing member by the pullcontrol device.
 14. The system of claim 13, wherein each of the push andpull control devices includes a supporting ring configured to support aportion of the probing member to maintain at a desired position of theprobing member in relation to the push and pull control devices.
 15. Thesystem of claim 13, wherein the pull control device includes a clampingelement movable in relation to the pull control device and configured toreleasably secure to the internal member, the push control deviceincludes a clamping element movable in relation to the push controldevice and configured to releasably secure to the probing member, andeach of the push and pull control devices is further configured tocontrol movement and securement of the respective clamping device so asto effect application of a respective one of the pushing and pullingforces.
 16. The system of claim 15, wherein each clamping element of thepush and pull control devices includes a first pair of opposing clampsand a second pair of opposing clamps spatially offset from the firstpair of opposing clamps, and each of the push and pull control devicesis further configured to selectively alternate control of movement andsecurement between the respective first pair of opposing clamps and therespective second pair of opposing clamps to effect application of therespective one of the pushing and pulling forces.
 17. The system ofclaim 11, wherein the probing member is a colonoscope, the internalmember is an obturator, and the coupling member of the pull controldevice is securable to the obturator.
 18. A method for propelling acolonoscope within an intestine of a subject, wherein the colonoscopeincludes a scope housing, an obturator channel disposed within andextending between proximal and distal ends of the scope housing, theobturator channel being secured to the scope housing such that movementof the obturator channel effects movement of the scope housing, and anobturator disposed within the obturator channel and extending beyond theproximal end of the scope housing, the obturator being secured to asection of the obturator channel at a securing location proximate thedistal end of the scope housing, the method comprising: (a) insertingthe distal end of the scope housing into the intestine of the subject ata selected insertion point; and (b) applying a force to the obturator ata location proximate the proximal end of the scope housing to effect acorresponding pulling force on the obturator channel at the securinglocation and the distal end of the scope housing, wherein the pullingforce results in a corresponding movement of the distal end of the scopehousing within the intestine that increases or decreases an intestinalpath distance between the distal end of the scope housing and theinsertion point.
 19. The method of claim 18, further comprising: (c)applying a force to the scope housing at a selected distance from theproximal end of the scope housing and in a direction corresponding tothe force applied to the obturator.
 20. The method of claim 19, wherein(b) includes:  (b.1) automatically applying the force to the obturatorvia a pull control device coupled to the obturator at the locationproximate the proximal end of the scope housing; and wherein (c)includes:  (c.1) automatically applying the force to the scope housingvia a push control device coupled to the scope housing at the selecteddistance from the proximal end of the scope housing.
 21. The method ofclaim 20, wherein the scope housing includes a looped section disposedbetween the push and pull control devices, and the method furthercomprises: (d) preventing any movement of the proximal end of the scopehousing in response to forces applied by the push and pull controldevices in (b.1) and (c.1) such that, when the distal end of the scopehousing is moved in a direction that increases the intestinal pathdistance between the distal end of the scope housing and the insertionpoint, the looped section decreases in length.
 22. The method of claim21, further comprising: (e) supporting a first end of the looped sectionof the scope housing via a first ring coupled to the pull controldevice, wherein the first end extends through the first ring; and (f)supporting a second end of the looped section of the scope housing via asecond ring coupled to the push control device, wherein the second endextends through the second ring.
 23. The method of claim 20, whereineach of the push and pull control devices includes a first and secondpair of clamps to control the forces applied to the obturator and thescope housing, wherein each pair of clamps is movable with respect to arespective one of the push and pull control devices and is releasablysecurable to a respective one of the obturator and the scope housing;and wherein (b.1) includes: (b.1.1) alternating control between thefirst pair of clamps and the second pair of clamps of the pull controldevice to apply the respective force to the obturator; and wherein (b.2)includes: (b.2.1) alternating control between the first pair of clampsand the second pair of clamps of the push control device to apply therespective force to the scope housing.
 24. A system for self-propellinga colonoscope within an intestine, the colonoscope including a scopehousing and an obturator extending within and protruding from a proximalend of the scope housing, the obturator being secured to the scopehousing at a location proximate the distal end of the scope housing, thesystem comprising: a means for applying a force to the obturator at theproximal end of the scope housing that effects a pulling movement of thedistal end of the scope housing in a direction toward or away from aninsertion point of the scope housing within the intestine.
 25. Thesystem of claim 24, further comprising: a means for applying a force tothe scope housing in a direction that corresponds to the force appliedto the obturator.